Association of Plumbing and Heating Contractors: http://www.aphc.co.uk/ 

Heating and Ventilation: http://www.heatingandventilating.net/

Modern Building Services: http://www.modbs.co.uk/

Green Living Ideas: http://www.motherearthnews.com/Green-Homes.aspx

Energy Conservation: http://www.energystar.gov/